CN114740292A - Lightning arrester operation state assessment method - Google Patents

Abstract

The invention relates to an arrester operation state evaluation method, which comprises the following steps: the method comprises the following steps that an operating voltage measuring end and an arrester full current detecting end are arranged on an arrester, and the operating voltage measuring end is used for collecting three-phase operating voltage acting on the arrester to obtain phase voltage parameters; the lightning arrester full current detection end is used for acquiring a three-phase full current signal flowing through the lightning arrester to obtain current parameters; and calculating according to the phase voltage parameters and the current parameters acquired by the operating voltage measuring end and the arrester full current detecting end to obtain test data, wherein the test data comprises one or more of phase difference, a resistive current peak value, a capacitive current peak value and each subharmonic component, comparing the test data with a corresponding typical value, and judging the operating state of the arrester. Compared with the prior art, the method can comprehensively reflect the overall operation condition of the zinc oxide arrester, is less influenced by voltage fluctuation of a power grid system, and has the advantages of high detection speed, excellent sensitivity, high accuracy and the like.

Description

Lightning arrester operation state assessment method

Technical Field

The invention relates to the technical field of lightning arrester monitoring, in particular to a lightning arrester running state assessment method.

Background

Lightning arresters are mainly used to limit overvoltages in systems. For the power system, once abnormal conditions such as lightning stroke or overvoltage occur, in order to avoid the insulation damage of related power equipment, the lightning arrester can introduce high voltage into the ground, so that the large voltage loaded on the protected equipment is rapidly reduced, the insulation protection of the related power equipment is realized, and the continuous and stable operation of the power equipment is further ensured. Since the early 20 th century, the lightning arrester has been born and has undergone nearly one hundred years of research, application and technical innovation, and the overall performance of the lightning arrester has made a great progress. Among them, the zinc oxide arrester has become the most widely used arrester by virtue of excellent nonlinear characteristics.

By means of the wide application of the zinc oxide lightning arrester, the power grid accident rate caused by lightning overvoltage is greatly reduced. Therefore, the normalized monitoring of the comprehensive performance of the zinc oxide arrester becomes an important task for operation and maintenance personnel of a power grid system, but the problems of large number of substations, few first-line testers, time and labor waste in detection and the like become a big pain point for the performance monitoring of the zinc oxide arrester.

At present, the performance monitoring of the zinc oxide arrester mainly comprises the following two methods:

1. all current method

The full current method adopts an alternating current meter connected in series in a grounding circuit of the zinc oxide arrester to realize the measurement of the total leakage current (full current) flowing through the arrester. The capacitive current component Ic in the total leakage current is determined by the inherent capacitance of the arrester, and the value of the capacitive current component Ic is basically unchanged, so that the change of the total leakage current reflects the change of the resistive current component in the arrester to a great extent. Therefore, the overall performance of the lightning arrester can be judged by detecting the current change.

The full current method has the characteristics of simple operation and low cost, and can well detect and identify serious lightning arrester faults, but because the resistive current component only accounts for a very small part of the total leakage current, the method is insensitive to early-stage or slight faults (such as chronic damp) of the lightning arrester, the detection accuracy is not high, and the detection method is greatly influenced by the environmental temperature.

2. Third harmonic method

The measurement principle of the third harmonic method is shown in fig. 1. The measurement of the total leakage current of three phases of the lightning arrester is realized by connecting a current transformer CT in series in a grounding circuit of the three-phase lightning arrester. When the lightning arrester normally operates, for the measured three-phase total leakage current, the harmonic influence of a power grid is not considered, fundamental current components in the total leakage current are mutually offset due to the difference of 120 degrees, and therefore the actual measurement is the sum of three-phase third harmonic current; when a phase arrester fails, the fundamental current component of the phase can be obviously increased, so that the fundamental current component cannot be completely offset, and the measured total leakage current is obviously increased.

The third harmonic method has the characteristics of simple and convenient field installation and less required equipment, and can directly obtain the harmonic current component flowing through the zinc oxide for lightning protection without collecting the system voltage. However, due to the fact that the relationships between the third harmonic resistive components and the total resistive current components of different lightning arresters are different and harmonic interference exists in the power grid system, certain errors exist in the measurement of the method, and the method cannot directly judge which phase of lightning arrester has a problem.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the lightning arrester operating state evaluation method which is rapid in detection, excellent in sensitivity and high in accuracy.

The purpose of the invention can be realized by the following technical scheme:

the invention also provides an arrester operation state evaluation method, which comprises the following steps:

the method comprises the steps that an operating voltage measuring end and an arrester full current detecting end are arranged on an arrester, wherein the operating voltage measuring end is used for collecting three-phase operating voltage acting on the arrester to obtain phase voltage parameters; the lightning arrester full current detection end is used for acquiring a three-phase full current signal flowing through the lightning arrester to obtain current parameters;

and calculating according to phase voltage parameters and current parameters acquired by the operating voltage measuring end and the arrester full current detecting end to obtain test data, wherein the test data comprises one or more of phase difference, a resistive current peak value, a capacitive current peak value and each subharmonic component, comparing the test data with a corresponding typical value, and judging the operating state of the arrester.

Furthermore, the operating voltage measuring end comprises phase voltage acquisition equipment, a first conditioning module, a first analog-to-digital conversion module, a first GPS time service module, a first microcontroller module and a first wireless transmission module, wherein the first microcontroller module is respectively connected with the first analog-to-digital conversion module, the first GPS time service module and the first wireless transmission module, the first conditioning module is respectively connected with the phase voltage acquisition equipment and the first analog-to-digital conversion module, and the phase voltage acquisition equipment is arranged on a three-phase power wire of the lightning arrester;

the first microcontroller module drives phase voltage acquisition equipment to acquire three-phase operating voltage acting on the lightning arrester under the set condition of a first GPS time service module, performs signal conditioning through a first conditioning module and performs analog-to-digital conversion through a first analog-to-digital conversion module, and then performs operation processing to acquire phase voltage parameters; and finally, transmitting the phase voltage parameters to a human-computer interaction terminal through a first wireless transmission module, and evaluating the running state of the lightning arrester in the human-computer interaction terminal.

Further, the phase voltage parameters include a fundamental amplitude, harmonic components and an initial phase of the phase voltage signal.

Furthermore, the first microcontroller module converts the data after the analog-to-digital conversion into a frequency domain through fast Fourier transform for analysis, and phase voltage parameters are obtained.

Further, the first microcontroller module is an STM32 microcontroller.

Furthermore, the lightning arrester full current detection end comprises full current acquisition equipment, a second conditioning module, a second analog-to-digital conversion module, a second GPS time service module, a second microcontroller module and a second wireless transmission module, the second microcontroller module is respectively connected with the second analog-to-digital conversion module, the second GPS time service module and the second wireless transmission module, the second conditioning module is respectively connected with the full current acquisition equipment and the second analog-to-digital conversion module, and the full current acquisition equipment is installed on a three-phase power line of the lightning arrester;

the second microcontroller module drives the full current acquisition equipment to acquire three-phase full current signals acting on the lightning arrester under the set condition of the second GPS time service module, and acquires current parameters after signal conditioning is performed by the second conditioning module and analog-to-digital conversion is performed by the second analog-to-digital conversion module; and finally, the current parameters are transmitted to the man-machine interaction terminal through the second wireless transmission module, and the running state of the lightning arrester is evaluated in the man-machine interaction terminal.

Further, the second microcontroller module is an STM32 microcontroller.

And further, the operating state of the lightning arrester is monitored by adopting the phase angle difference between the phase voltage and the fundamental current.

Compared with the prior art, the invention has the following advantages:

the invention combines the main advantages of the fundamental wave method and the third harmonic wave method, realizes the simultaneous acquisition of the operating voltage on the arrester and the total leakage current of the arrester through a voltage transformer and a current transformer, converts the signals into a frequency domain for analysis through the fast Fourier transform after the analog/digital conversion, and can separate out the required resistive current fundamental wave and each subharmonic component through certain operation processing, thereby realizing the detection and the judgment of the overall performance of the zinc oxide arrester.

According to the measured parameters of the resistive current fundamental component, the resistive current peak value, each subharmonic component and the like, the harmonic analysis method can comprehensively reflect the whole operation condition of the zinc oxide arrester. Meanwhile, the method is less influenced by voltage fluctuation of the power grid system, and has the characteristics of high detection speed, excellent sensitivity and high accuracy.

Drawings

FIG. 1 is a schematic diagram of the measurement principle of the third harmonic method provided in the background of the invention;

fig. 2 is a schematic hardware structure diagram of a lightning arrester operation state evaluation method provided in an embodiment of the present invention;

fig. 3 is a schematic diagram of a test result of an a-phase lightning arrester provided in an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

Example 1

As shown in fig. 2, the present embodiment provides a method for evaluating an operating state of an arrester, including the following steps:

the method comprises the following steps that an operating voltage measuring end and an arrester full current detecting end are arranged on an arrester, and the operating voltage measuring end is used for collecting three-phase operating voltage acting on the arrester to obtain phase voltage parameters; the lightning arrester full current detection end is used for acquiring a three-phase full current signal flowing through the lightning arrester to obtain current parameters;

and calculating according to the phase voltage parameters and the current parameters acquired by the operating voltage measuring end and the arrester full current detecting end to obtain test data, wherein the test data comprises one or more of phase difference, a resistive current peak value, a capacitive current peak value and each subharmonic component, comparing the test data with a corresponding typical value, and judging the operating state of the arrester.

The method combines the main advantages of a fundamental wave method and a third harmonic wave method, realizes simultaneous acquisition of operating voltage on the arrester and total leakage current of the arrester through a voltage transformer and a current transformer, converts the signals into a frequency domain for analysis through analog/digital conversion, and can separate required resistive current fundamental wave and each subharmonic component through certain operation processing, thereby realizing detection and judgment of the overall performance of the zinc oxide arrester.

According to the measured parameters of the resistive current fundamental component, the resistive current peak value, each subharmonic component and the like, the harmonic analysis method can comprehensively reflect the whole operation condition of the zinc oxide arrester. Meanwhile, the method is less influenced by voltage fluctuation of the grid system, and has the characteristics of high detection speed, excellent sensitivity and high accuracy.

Specifically, the operating voltage measuring end comprises phase voltage acquisition equipment, a first conditioning module, a first analog-to-digital conversion module, a first GPS time service module, a first microcontroller module and a first wireless transmission module, wherein the first microcontroller module is respectively connected with the first analog-to-digital conversion module, the first GPS time service module and the first wireless transmission module;

the first microcontroller module drives phase voltage acquisition equipment to acquire three-phase operating voltage acting on the lightning arrester under the set condition of a first GPS time service module, performs signal conditioning through a first conditioning module and analog-to-digital conversion through a first analog-to-digital conversion module, and performs operation processing to acquire phase voltage parameters, wherein the phase voltage parameters comprise fundamental wave amplitude, harmonic components and initial phases of the phase voltage signals; and finally, transmitting the phase voltage parameters to a human-computer interaction terminal through a first wireless transmission module, and evaluating the running state of the lightning arrester in the human-computer interaction terminal.

The first microcontroller module converts the data after the analog-to-digital conversion into a frequency domain for analysis through fast Fourier transform, and phase voltage parameters are obtained. In this embodiment, the first microcontroller module is an STM32 microcontroller.

The lightning arrester full current detection end comprises full current acquisition equipment, a second conditioning module, a second analog-to-digital conversion module, a second GPS time service module, a second microcontroller module and a second wireless transmission module, wherein the second microcontroller module is respectively connected with the second analog-to-digital conversion module, the second GPS time service module and the second wireless transmission module;

the second microcontroller module drives the full current acquisition equipment to acquire three-phase full current signals acting on the lightning arrester under the set condition of the second GPS time service module, and acquires current parameters after signal conditioning is performed by the second conditioning module and analog-to-digital conversion is performed by the second analog-to-digital conversion module; and finally, the current parameters are transmitted to the man-machine interaction terminal through the second wireless transmission module, and the running state of the lightning arrester is evaluated in the man-machine interaction terminal.

In this embodiment, the second microcontroller module is an STM32 microcontroller.

The man-machine interaction terminal receives key parameters of phase voltage and current signals sent by the operating voltage measuring end and the lightning arrester full current detecting end, and data such as phase difference, a resistive current peak value, a capacitive current peak value and each subharmonic component can be obtained through a series of calculation processing. On the basis, the test data is compared with the relevant typical values, and finally, the overall performance and the working state of the lightning arrester are judged.

The test is only carried out by taking the A-phase lightning arrester (CH0) as an example. The test results are shown in fig. 3.

In the specific diagnosis test, the characteristic that the capacitive current component in the total current of the lightning arrester is basically unchanged is considered, and the phase angle difference between the phase voltage and the fundamental current is adopted to monitor the overall operation state of the lightning arrester, so that the method is simpler, more convenient and more efficient. The overall operating condition of the zinc oxide arrester can be evaluated with reference to table 1, according to the requirement that the resistive current component does not exceed 25% of the full current.

TABLE 1

During testing, alternating current high voltage of about 10kV is applied to the zinc oxide lightning arrester to be tested, and the phase angle difference between the phase voltage and the fundamental current obtained through measurement is stabilized at about 82 degrees, which shows that the overall performance of the zinc oxide lightning arrester to be tested is good. Meanwhile, the test result also shows that the designed arrester on-line monitoring system can realize the real-time monitoring of the running state of the arrester, has good diagnosis accuracy and basically achieves the expected design target.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (8)

1. An arrester operation state evaluation method is characterized by comprising the following steps:

the method comprises the steps that an operating voltage measuring end and an arrester full current detecting end are arranged on an arrester, and the operating voltage measuring end is used for collecting three-phase operating voltage acting on the arrester and obtaining phase voltage parameters; the lightning arrester full current detection end is used for acquiring a three-phase full current signal flowing through the lightning arrester to obtain current parameters;

and calculating according to the phase voltage parameters and the current parameters acquired by the operating voltage measuring end and the arrester full current detecting end to obtain test data, wherein the test data comprises one or more of phase difference, a resistive current peak value, a capacitive current peak value and each subharmonic component, comparing the test data with a corresponding typical value, and judging the operating state of the arrester.

2. The method for evaluating the operating state of the lightning arrester according to claim 1, wherein the operating voltage measuring terminal comprises a phase voltage acquisition device, a first conditioning module, a first analog-to-digital conversion module, a first GPS time service module, a first microcontroller module and a first wireless transmission module, the first microcontroller module is respectively connected with the first analog-to-digital conversion module, the first GPS time service module and the first wireless transmission module, the first conditioning module is respectively connected with the phase voltage acquisition device and the first analog-to-digital conversion module, and the phase voltage acquisition device is installed on a three-phase power wire of the lightning arrester;

the first microcontroller module drives phase voltage acquisition equipment to acquire three-phase operating voltage acting on the lightning arrester under the set condition of a first GPS time service module, performs signal conditioning through a first conditioning module and performs analog-to-digital conversion through a first analog-to-digital conversion module, and then performs operation processing to acquire phase voltage parameters; and finally, transmitting the phase voltage parameters to a human-computer interaction terminal through a first wireless transmission module, and evaluating the running state of the lightning arrester in the human-computer interaction terminal.

3. The method according to claim 2, wherein the phase voltage parameters include a fundamental amplitude, harmonic components, and an initial phase of the phase voltage signal.

4. The method for evaluating the operating condition of the lightning arrester according to claim 2, wherein the first microcontroller module converts the data after the analog-to-digital conversion into a frequency domain for analysis through fast fourier transform to obtain the phase voltage parameters.

5. The method for assessing the operating condition of an arrester according to claim 2, wherein the first microcontroller module is an STM32 microcontroller.

6. The method for evaluating the operating state of the lightning arrester according to claim 1, wherein the lightning arrester full current detection end comprises a full current acquisition device, a second conditioning module, a second analog-to-digital conversion module, a second GPS time service module, a second microcontroller module and a second wireless transmission module, the second microcontroller module is respectively connected with the second analog-to-digital conversion module, the second GPS time service module and the second wireless transmission module, the second conditioning module is respectively connected with the full current acquisition device and the second analog-to-digital conversion module, and the full current acquisition device is installed on a three-phase power line of the lightning arrester;

the second microcontroller module drives the full current acquisition equipment to acquire three-phase full current signals acting on the lightning arrester under the set condition of the second GPS time service module, and acquires current parameters after signal conditioning is performed by the second conditioning module and analog-to-digital conversion is performed by the second analog-to-digital conversion module; and finally, the current parameters are transmitted to the man-machine interaction terminal through the second wireless transmission module, and the running state of the lightning arrester is evaluated in the man-machine interaction terminal.

7. The method for assessing the operating condition of an arrester according to claim 6, wherein the second microcontroller module is an STM32 microcontroller.

8. The method according to claim 1, wherein the operating state of the arrester is monitored using a phase angle difference between the phase voltage and the fundamental current.

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